1. Field of the Invention
The present invention generally relates to a paper feeding device, and more particularly to a paper feeding device capable of stabilizing paper feeding speeds and decreasing a manufacturing cost thereof.
2. The Related Art
Referring to FIG. 8, a conventional paper feeding device 100′ generally includes a pickup assembly 10′, a separation assembly 20′ disposed above the pickup assembly 10′, a first paper feeding assembly 30′ disposed behind the pickup assembly 10′, a second paper feeding assembly 40′ disposed above the first paper feeding assembly 30′, two ultrasonic sensors 50′ disposed oppositely and spaced from each other, a signal processor 60′ electrically connected between the two ultrasonic sensors 50′, a transmission assembly 70′ connected with the pickup assembly 10′ and the first paper feeding assembly 30′, and a motor 80′ connected with the transmission assembly 70′.
The paper feeding device 100′ defines a paper feeding channel 90′. The motor 80′ drives the pickup assembly 10′ and the first paper feeding assembly 30′ to rotate by virtue of the transmission assembly 70′ to make paper 200′ fed into the paper feeding channel 90′ of the paper feeding device 100′. When the paper 200′ is passed through an interval between the two ultrasonic sensors 50′, one ultrasonic sensor 50′ sends an ultrasonic signal, and the other ultrasonic sensor 50′ receives the ultrasonic signal. The signal processor 60′ analyzes a size of the ultrasonic signal for determining whether there are multiple pieces of paper 200′ fed into the paper feeding channel 90′ of the paper feeding device 100′. So the conventional paper feeding device 100′ determines an abnormal paper feeding condition.
However, the conventional paper feeding device 100′ determines the abnormal paper feeding condition by virtue of the two ultrasonic sensors 50′ and the signal processor 60′ that increases a manufacturing cost of the paper feeding device 100′. Moreover, the conventional paper feeding device 100′ has no way of detecting paper feeding speeds, so the paper feeding speeds are hardly stabilized.